LED Torch (flashlight) Conversion – Build

Ok, so i designed my torch. This is fine but designs are no good unless you actually put them into practice. This is quite a quick build that goes together nice and quickly and has some nice satisfactory results:

I started by taking cutting out 2 discs from the aluminium plate using the aviation snips. I finished the edge of the discs with a flat file. The discs should fit snugly inside the top of the torch body (about the same size as the circuit board).

Next I got the circuit board:

You can see it has three LEDs soldered on and a resistor, we don’t need these so I ripped them off with pliers

I then cut a notch in the side of the aluminium discs and in the side of the circuit board using a hack saw (don’t worry about cutting the tracks, we don’t need them all). This is to route the wires through.

My next job was to solder the wires and resistor to the LED. First I soldered the resistor onto the end of the red wire then soldered the other end of the resistor onto the +ve terminal of the LED, finally I soldered the black wire onto the -ve terminal of the LED. I found the best way to do this was to put a blob of solder on the LED pads and to tin the ends of the wire/resistor. You want the exposed bits of wire to be as short as possible. I then placed heatshrink over the resistor to protect it:

I then arranged the circuit board, plastic sheet, aluminium discs and led in order so that i could measure the exact length of wire i would need and trimmed it to length. The red wire (with the resistor) is then soldered to the +ve battery pick up and the black wire is soldered to one of the blobs of solder at the edge of the circuit board. I also put extra blobs of solder around the edge of the circuit board so that it would sit flat:

Then i placed the circuit board in the torch body, followed by a circle of plastic, followed by a aluminium disc, then i spread thermal paste all over this disc (you want enough so that some pushes up the edges of the next disc you put on). Once both discs were in, I put another blob of thermal paste in the middle of the top disc and pressed the LED onto this. The LED is then held down with blobs of hot glue around the edge. The final result should look a little like this:

You could just leave the torch like this, but this is a very wide angle LED so doesn’t give a very good beam. I’m going to add a lens to this to improve the focus.